(Solved) A 220 Ω resistor is connected in series with the gate of an SCR as shown in fig. The gate current required to fire the SCR is 7 mA. What is the input voltage (Vin) required to fire the SCR?

 Question :

A 220 Ω resistor is connected in series with the gate of an SCR as shown in fig. The gate current required to fire the SCR is 7 mA. What is the input voltage (Vin) required to fire the SCR?

Answer :

Vin will not be equal to only IG * R but we have to add junction voltage 0.7 volt also. 

So correct Vin = 0.7 + IG*R = 0.7 + (7mA)(220 ohm)

Vin = 2.24 V